Ask Dr. Shankar is a monthly feature that answers your most pressing questions about the health impacts associated with exposure to air pollution. Dr. Shankar Prasad is an executive fellow with CCA and has spent five years in clinical practice, three years conducting research on the health effects of air pollution and 22 years in environmental health research and policy development. Learn more about Dr. Prasad below.
We encourage people from all corners of California to submit their air quality/health-related questions to askthedoc@coalitionforcleanair.org. We will answer one question each month and post it on this blog.
Are motorcycles environmentally friendly?
March 19, 2010
Q: In recent years, I have noticed an increase in the number of motorcycles on the freeways. Are these more fuel efficient and good for the environment?
- Morton Butcher
A: Dear Mr. Butcher,
During the early ‘90s, around 300,000 motorcycles were sold each year in California. This number increased steadily and then stayed between 800,000 and 1.1 million from 2001 through 2008. Many people believe that motorcycles are good for the environment because of their engine size and fuel economy; but this perceived notion is not necessarily true.
The emissions per mile of the primary smog-forming compounds (nitrogen oxides + reactive organics) from a typical motorcycle is 190 times more than a clean car (5.21 g/mi vs. 0.03 g/mi) sold in the state in 2005. Similarly, the emissions from one gallon of gasoline used in a motorcycle is 320 times more than those coming from a 2005 model year clean passenger car (199.8 g/gallon vs. 0.62 g/gallon).
Though the total contribution of smog-forming compounds from this segment may currently be relatively small, the trend of increasing numbers is worrisome. In addition, while emissions from other mobile sources (cars, trucks and even off-road vehicles or equipment) are closely monitored and regulated, motorcycles’ emissions have never been equally well regulated or monitored. Many efforts to remedy the situation through legislation continue to fail because of the intense lobbying efforts and lack of support in the legislature.
More information:
- http://www.arb.ca.gov/msprog/motcycle/motcycle.htm
- http://www.arb.ca.gov/msprog/offroad/orrec/orrec.htm
How can I test or filter my indoor air?
February 11, 2010
Q: We work in a 2-story building located next to an I-5 freeway overpass. Our HVAC equipment on the roof is only 50-75 feet from the traffic lanes and draws air into our building. Are there standards or protocols we can consider for testing and filtering our indoor air?
Kreigh Hampel
A: Dear Mr. Hampel,
The major pollutants of concern in your case are fine and ultrafine particles, as well as some organics from freeway vehicle exhaust and nearby roads. Acute adverse health effects associated with this type of pollution include increased incidence of cough, nasal irritation, lung infection, allergy symptoms, asthma and a worsening of chronic lung conditions. Chronic effects could also include cancer and even premature death.
One of the ways you can minimize the entry of outdoor pollution is by moving the direction of air intake away
from the pollution source—the freeway in your case—and adding fine particle filters to your existing HVAC system.
Recently the South Coast Air Quality Management District conducted a study to investigate the effectiveness of three different air purification systems in reducing children’s exposure to air contaminants inside classrooms. The study concluded that the most effective solution for reducing indoor concentrations of fine and ultrafine particle pollutants is to add specific types of filters where air enters the system and the classrooms. The removal efficiency was more than 87 percent.
The Indoor Air Quality Guide: Best Practices for Design, Construction and Commissioning is a new guide for achieving enhanced indoor air quality in large buildings.
After some research, however, I found no established method or protocol for evaluation or indoor pollutant standards for comparison.
More information:
- http://www.ashrae.org/publications/page/1936
- http://www.aqmd.gov/rfp/attachments/2010/AQMDPilotStudyFinalReport.pdf
- http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_2.html
- http://www.arb.ca.gov/research/indoor/indoor.htm
- http://www.epa.gov/iaq/largebldgs/index.html
Are air fresheners bad for my health?
January 20, 2010
Q: I am a mother of four and I substitute teach. Since I began subbing, I’ve come to realize that many teachers and staff members believe that plugging in an air freshener in the classroom, staff lounge or staff restroom freshens the air. I have asthma, and according to reports so do many children living in the valley. One of the things my doctor suggests to avoid are air fresheners, but I find it impossible to do! I am not only concerned about myself and my own children, but what about the air quality of the classroom which children are forced to be in for nearly seven hours every single day of the school year! With the Williams Act in place, which covers safety, does not this qualify as being unsafe for children and myself? There are many chemicals being emitted into the air that we are as a society just accepting as the norm. If it is on the shelf at the store, then it must be safe! Am I the only one worried about this? How can I as one person get air fresheners and chemicals out of the classrooms? —Natalie
A: Dear Natalie,
I understand your concern. You have rightly pointed out that we as a society seem to accept the fact that a product or a chemical sold on the market is deemed safe for the consumer. Compared to many other states, California has higher safety standards for outdoor air quality. The California Air Resources Board has the authority to regulate consumer products, should their use affect outdoor air quality. However, there is no agency that has a clear-cut authority to regulate indoor air quality, except in the context of Cal OSHA with respect to workers’ health. The problem is that most worker-related product safety protections are set for a healthy person, not for a susceptible or sensitive individual such as you.
Smog in the classroom
Air fresheners and cleaning products used in schools contain a wide variety of hazardous chemicals that increase indoor air pollution and harm health. According to the U.S. EPA, half of the nation’s schools have poor indoor air quality. Studies have even linked bad indoor air quality to reduced test scores of students.
Learn more about the dirty truth of bad air quality in our schools (English and Español)
Take action
Urge your school management to stop using air fresheners—they affect your health and that of our students. Garner support from teachers associations, PTAs and organizations who can help strengthen your case for clearing the air in your classroom.
Learn more ways to get educated and get involved: contact Luis Cabrales, CCA’s deputy director of campaigns.
How do idling vehicles affect my health?
December 10, 2009
Q: Hi – Thanks for your time to help improve air quality and health! I have been working to reduce unnecessary vehicle idling, particularly at schools where children are more susceptible to pollutants from vehicle exhaust. I wonder if you could address the pollutants that actually enter the idling vehicle, thereby polluting the driver/passengers in the vehicle. Is the driver/passenger also negatively affected by their own idling?
Thanks!
Donna
A: Dear Donna,
Briefly, more than 75 percent of school buses use diesel as fuel. The primary pollutant of concern is the diesel exhaust that includes fine particles and a number of other chemicals that are known to exacerbate asthma and can potentially cause cancer. The California Air Resources Board (CARB) has conducted a good evaluation of this issue, which concludes:
- Older buses may experience up to 2.5 times more pollution from the bus’ own exhaust that enters the cabin when the windows are closed.
- Exposure and associated risks are mainly influenced by other traffic-related emissions encountered while traveling in the bus, not by the time spent at bus stops or while loading and unloading.
- Assuming a 13-year commute by bus (more than an hour each way) a child’s lifetime risk, attributable to diesel pollution, is estimated to increase the risk of cancer by four percent, respiratory illnesses by six percent and hospital admissions for asthma by one percent
- Commuting by bus is still safer in comparison to the risk associated with automobile accident deaths.
- The results should not deter you from allowing your child to ride in a school bus.
California continues its efforts to reduce children’s and the public’s exposure to diesel pollution by retrofitting buses with particulate traps, restricting the idling of buses and trucks, reducing the sulfur content of diesel fuel, and restricting the emission limits of the newest fleets.
Learn more from CARB
Are new diesel cars good for the environment?
October 21, 2009
Q: Dear Dr. Shankar,
I hear that the new diesel cars are an even better environmental choice than hybrids or biodiesel. Can this be true, and if so, why don’t we hear as much buzz about it?
Thanks!
Leigh Stafford
A: Gasoline vs. diesel vehicles
In my opinion, new diesel cars are better for the environment when compared to the similar class and type of gasoline counterparts. The diesel fuel has a higher energy content and new diesel cars’ internal combustion power systems are more efficient, typically delivering 20 to 40 percent more miles per gallon and 10 to 20 percent fewer greenhouse gas (GHG) emissions.
According to the U.S. EPA, a simple comparison between diesel and gasoline versions of the Volkswagen Jetta demonstrated that the diesel model would travel 36 percent more miles on a tank of fuel, saving $321 annually on fuel costs, while using nearly two fewer barrels of oil and emitting one less ton of GHG emissions per year. A similar comparison between the 2007 Mercedes E320 Bluetec diesel and its E350 counterpart showed that the diesel model travels 43 percent more miles on a tank of fuel, saving $492 annually on fuel costs, while using 3.2 fewer barrels of oil and emitting 1.5 fewer tons of GHG emissions per year.
In addition, the UC Davis and UC Berkeley teams led by Dr. Alex Farrell and Dr. Dan Sperling have reported that when two identical vehicles (gasoline powertrain and new diesel technology) were compared on a well-to-wheels life cycle basis, the diesel had a 22 percent per-mile CO2 advantage. Similarly, a report by the California Air Resources Board (CARB) on low-carbon fuel standard found that “on a well-to-wheel life cycle basis, diesel fuel generates less CO2 per unit of energy than does gasoline, if all other factors are held constant.” Convinced of these facts, I recently purchased and drive a diesel car myself.
The Toyota Prius and Honda Civic hybrids are rated by CARB as SULEV—super ultra-low emission vehicles. Today’s new clean diesels, such as the VW Jetta, are rated by CARB as ULEV, or ultra-low emission vehicles, a notch down from SULEV. Hence, it may not be appropriate to compare between these two different classes of vehicles. SULEVs emit one-third of smog-forming emissions compared to ULEVs. However, recent announcements by many European automakers make it clear that diesel vehicles to be produced in future model years will be certified as SULEV. It is also important to note that any hybrid vehicle compared to its own non-hybrid version provides better fuel economy.
In terms of GHG emissions, new diesel vehicles—especially SULEVs—can be viewed as a very agreeable near-term solution until more plug-in electric vehicles, battery electric vehicles or hydrogen fuel cell vehicles comprise a majority of California’s overall vehicle fleet. Thus, it appears that if more Californians were to shift to clean diesel passenger vehicles, they would help the state meet its energy and climate change goals (i.e., Global Warming Solutions Act, California Low Carbon Fuel Standard, the California Energy Commission’s Bioenergy Action Plan and other energy policies) faster and at less cost than previously estimated. In order to have this effect, though, these vehicles must continue to comply with California’s light-duty vehicle emission standards and have particulate filters as recent ones do.
For more information on this topic, view CARB’s A Low-Carbon Fuel Standard for California or the U.S. Department of Energy’s page on diesel vehicles.
The “Biodiesel” question
This aspect is more complex than it appears; thus, it will be answered in the future after doing some research and homework.
Are home air purifiers effective?
October 1, 2009
Q: Hi Dr. Shankar,
I have an air purifier and one of the settings is “ionize.” What does this mean to me and my indoor air? Also, do air purifiers create ozone, and how does that affect me? -Carla
A: Dear Carla,
In general, good housekeeping practices and using high quality air intake filters for a central air conditioning system are sufficient to maintain healthy indoor air quality. Some may find a need to use an indoor air purifier because of a medical condition, such as severe allergies, asthma or other reasons by which the indoor air quality is deteriorating. The following three documents from the California Air Resources Board provide more details and background information:
Beware of ozone-generating indoor “air purifiers”:
http://www.arb.ca.gov/research/indoor/ozone_gen_fact_sheet-a.pdf
FAQ on air cleaning devices for the home:
http://www.arb.ca.gov/research/indoor/acdsumm.pdf
California certified air cleaning devices:
http://www.arb.ca.gov/research/indoor/aircleaners/certified.htm
What is the air quality in my neighborhood?
October 1, 2009
Q: Hello Doctor,
I live south of Hollywood, near Koreatown. Generally, ( not when there are fires) is the air better here than in the san Fernando Valley or the Ports, and if so, how much better?
Thank You, Mitchell
A: Dear Mitchell,
In relative terms, the air quality in Koreatown is better than both the Valley and port areas. In 2007, the Koreatown area had fewer days exceeding the safe exposure level for ozone when compared to Burbank or Reseda, and the cancer risk is also lower when compared to port areas. In contrast, it appears that the difference in fine particles levels is not as significant. The nearest monitoring site to Koreatown is located on North Main Street in Los Angeles.
The South Coast Air Quality Management District—the air pollution control agency for all of Orange County and the urban portions of Los Angeles, Riverside and San Bernardino counties—offers various maps of air pollution by neighborhood:
• Daily air quality forecasts and advisories:
http://www2.aqmd.gov/webappl/gisaqi2/VEMap3D.aspx
• Review of air toxics (mostly diesel pollution) at the neighborhood level; interactive map of the South Coast Air Basin that identifies your carcinogenic risk:http://www2.aqmd.gov/webappl/matesiii/
The California Air Resources Board offers these air pollution indicators:
• Learn about present or past ozone air quality from the Air Quality and Meteorological Information System:http://www.arb.ca.gov/aqmis2/aqinfo.php
• These air quality data statistics allow you to select and view air quality data for various pollutants throughout California:http://www.arb.ca.gov/adam/welcome.html
What impact do wildfires have on my health?
September 1, 2009
Q: Dear Dr. Shankar,
I live in an area that is susceptible to wildfires. Every year, fires rip through the mountains, ravaging vegetation and homes and wreaking havoc on my ability to breathe. What are some of the health impacts associated with wildfires; and why are they happening more frequently and with greater intensity?
Sincerely, Hector
Santa Cruz, California
A: Dear Hector,
The principal health threat from short-term exposure to wildfire smoke is breathing toxic gases such as carbon monoxide (CO) and fine particulate matter (PM), a generic term for the hundreds of microscopic compounds, typically one-sixth the size of a human hair.
Wildfire smoke also contains significant quantities of respiratory and eye irritants, which can and cause coughing, wheezing, difficulty breathing, bronchitis and exacerbated asthma. Inhaling large amounts of PM in a short time can also dry out the membranes of the nose, mouth and throat, causing a scratchy, irritated feeling.
Typical CO exposure at low levels—such as from wildfire smoke—does not pose a significant hazard to the general public, except to sensitive individuals and to firefighters close to the fire line. Individuals who may experience exacerbated effects from smoke are typically those with heart disease, in which case a sufferer may experience chest pain and cardiac arrhythmias.
On smoky days, here are a few tips to stay healthy:
- Reduce physical activity to lower your body’s demand for oxygen.
- Stay indoors, keeping doors and windows shut. Run air conditioners with the intake valve closed.
- Without air conditioning, staying indoors on a hot day is not a good idea. Instead, leave the area and stay with friends or family members, or go to a clean air shelter.
- For more tips for staying healthy when a fire is near, click here.
So, why are wildfires happening more frequently and with greater intensity? The effects of global warming lead to heat waves and droughts, making wildfires more frequent and destructive. Global warming also prompts early snow melt, leading to drier conditions which amplify the effects of heat and seasonal thunderstorms. Forests, natural stores of CO2, release this trapped gas when burned, perpetuating the global warming cycle.
Although global warming may not be the only component contributing to increasingly severe fire seasons, it is a significant factor.
Shankar B. Prasad, M.B.B.S.
Dr. Shankar Prasad, executive fellow, has been with the Coalition for Clean Air since February 2008. Dr. Prasad is currently advocating the design of a cap-and-trade program capable of achieving maximum greenhouse gas emission reductions in the most polluted and marginalized communities. He is also currently advocating the passage of AB 1405, which creates a Community Benefits Fund to help local communities deal with the impacts associated with global warming.
Previously, as the Deputy Secretary for Science and Environmental Justice at the California Environmental Protection Agency (Cal/EPA), Dr. Prasad initiated and led the agency’s task to evaluate and improve the quality and role of science in the decision making process and was successful in securing funding to develop guidelines for incorporating cumulative impacts consideration into the regulatory process. During his tenure as Health Advisor to the Chairman of the California Air Resources Board, his efforts led to the board’s adoption of the environmental justice policies and funding to develop a cumulative impacts screening tool. Dr. Prasad also worked as a Health Effects Officer at the South Coast Air Quality Management District for five years.
In addition to being a member of the National Environmental Justice Advisory Committee, Dr. Prasad co-chairs its Goods Movement Working Group, which will recommend how the United States EPA can most effectively promote strategies in partnership with federal, state, tribal and local government agencies to identify, mitigate and/or prevent the disproportionate burdens in communities experiencing the impacts of air pollution resulting from the movement of products. Dr. Prasad has spent five years in clinical practice, three years conducting research on the health impacts of air pollution and 22 years in environmental health research and policy development.
*Dr. Shankar Prasad is not a practicing physician.
Thanks Dr. Shankar and CCA for the honest scientific answers about motorcycles! Too many people just look at CO2 emissions alone, and forget that there are many toxic components in exhaust that are what really makes the air unhealthy. A lot of the newer cars have made tremendous progress in reducing these pollutants to minuscule amounts – but motorcycles, lawnmowers and many other small engines are sadly not regulated.
Hello Doctor,
I have a peak flow meter and when I used it my reading was very low. 235
How good of an indicator of health is the peak flow meter and what should a reading be?
I’m 40 year old woman in generally good health
Hi Dr. Mitchell,
I am earning a Boy Scout merit badge called “Citizenship in the Community.” I have a couple of questions to ask you in regards to air quality in Los Angeles.
1)What is being done to make air quality better?
2) How can young people help to make the air cleaner?
Thank you so much,
Jacob Thornblad
Dear Jacob,
I am glad you are concerned about improving Los Angeles’ air quality and are taking proactive steps to inspire others to do the same.
Los Angeles’ air quality is far better than when I lived there in the early 1980s, and it continues to improve. This is primarily due to the efforts taken at the local level by the South Coast Air Quality Management District, which has been instrumental in reducing emissions from large and small stationary sources such as refineries, factories, cement plants, auto body paint shops and even dry cleaners. At the state level, the California Air Resources Board has focused primarily on reducing emissions from mobile sources, including cars, diesel trucks and even lawn mowers. In contrast, federal agencies that have the authority on planes, ships, ports and airports have not been as aggressive.
A basic thing to remember is that all activities need energy, much of which is produced by burning fossil fuels, and this leads to air pollution and climate change. Therefore, anything that reduces energy demand and fossil fuel use is beneficial to the environment.
Things you can do to help clear the air:
• Instead of having your parents drive you every time, try walking, biking or riding the bus; encourage your parents to join a carpool.
• Dry your clothes in the sun instead of using a dryer.
• Dress for the weather—even inside your home—so you don’t have to rely as much on your heater or air conditioner.
• Ask your parents or teachers if you can plant trees in the yard at home or at school.
• Recycle all bottles, cans, paper or other recyclable materials that you use; better yet, eliminate waste in the first place by carrying reusable bags and bottles.
Another thing you can do is to volunteer for organizations that work on air-friendly projects, such as increasing mass transit options or improving energy efficiency. And if you’re really passionate about air pollution issues, consider doing as I did: pursue a career in environmental science, advocacy or law.
Dear Dr. Shankar,
Thank you for your time and energy devoted to air quality research. I have lived for years in Topanga Canyon in the Santa Monica Mountains and have always wondered wether I was above the smog line, particulate matter and ozone. Is it healthier at higher altitudes or ground level? Also what would you say are the biggest contributors to air pollution and what can we do to promote cleaner and healthier air. Thank you so much!
Why are not Pro. 65 signs being use in communities which considered a “hot spot”?
Dear Dr. Shankar,
I hear that the new diesel cars are an even better environmental choice than hybrids or biodiesel. Can this be true, and if so, why don’t we hear as much buzz about it?
Thanks!
Dr. Shanker,
Please discuss the substance titanium dioxide. It supposedly helps clean the air, and has other benefits, but I also heard that Canada has banned its use because it is a carcinogen.
What does EPA and FDA say about it? And what is your stance on its use in this country?
Thanks,
Mina Fried
Hi Dr. Shankar,
I have an air purifier and one of the settings is “ionize.” What does this mean to me and my indoor air? Also, do air purifiers create ozone, and how does that affect me?
-Carla
Hello Doctor,
I live south of Hollywood, near Koreatown. Generally, ( not when there are fires) is the air better here than in the san Fernando Valley or the Ports, and if so, how much better?
Thank You, Mitchell