This blog post was written by Larry R. Soward, and it originally appeared on the Air Alliance Houston’s blog.
In our December 2012 article, “New Soot Standards Will Better Protect Public Health,” we wrote about the new, stricter national air quality standard for fine particulate matter adopted by the U.S. Environmental Protection Agency (EPA). Particulate matter (PM) is one of the six "criteria" pollutants considered harmful to public health and the environment for which the EPA is required to set National Ambient Air Quality Standards. PM that is 2.5 micrometers in diameter or smaller — called “fine particulate matter” or “PM2.5” and commonly known as “soot” — is of greatest concern because of its significant health effects on people with heart or lung diseases, children and older adults.
Because reductions in fine particle pollution have direct health benefits including decreased mortality rates, fewer incidents of heart attacks, strokes, and childhood asthma, the new PM 2.5 standard is predicted to have major economic benefits with comparatively low costs. The EPA estimates health benefits of the new standard to range from $4 billion to over $9 billion per year, while estimated costs of implementation range from $53 million to $350 million. While the EPA cannot consider costs in selecting a standard under the federal Clean Air Act, those costs are estimated as part of the careful analysis undertaken for all significant regulations.
Strongly supportive of this new, more health-protective standard is a landmark study recently announced at a conference of the American Association for the Advancement of Science and published in the American Heart Association journal. The study found a direct link between out-of-hospital cardiac arrests and levels of air pollution from PM and ozone. Conducted by Rice University researchers right here in Houston and based on 8 years of data collected from Houston's network of air quality monitors and more than 11,000 concurrent out-of-hospital cardiac arrests logged by Houston Emergency Medical Services, the study shows that the risk of cardiac arrest ratchets up significantly as the amount of air pollution increases.
Rice statisticians Katherine Ensor, a professor and chair of Rice's Department of Statistics, and Loren Raun, a research professor in the department, found that a daily average increase in fine particulate matter of 6 micrograms per day over two days raised the risk of cardiac arrest by 4.6 percent, with particular impact on those with pre-existing, but not necessarily cardiac-related, health conditions. The study also found that increases in ozone levels produced similar results, but in a compressed timeframe. Each increase of 20 parts per billion of ozone over one to three hours also increased the risk of cardiac arrest, reaching a peak of 4.4 percent. The risks were higher for men, African-Americans and people over age 65. Ensor and Raun noted that 55 percent of the cardiac arrest cases occurred during the summer months, the period of typically high ozone levels in Houston. Approximately 300,000 persons in the U.S. experience an out-of-hospital cardiac arrest each year, of which over 90 percent die.
Despite these revealing findings, the Texas Commission on Environmental Quality (TCEQ) continues to claim that scientific studies exposing humans to PM generally report very small associations between adverse health outcomes and PM2.5 concentrations in air. In its March newsletter, “Natural Outlook,” the TCEQ claims that the new PM standard is “unreasonably strict and unsupported by available scientific research” and “may not produce the intended improvements in human health.” TCEQ asserts, as it often does, that further research must be done because “many questions remain,” such as the nature of the risk posed by PM2.5; at what concentration of PM2.5 this risk may occur; who is actually harmed (e.g., elderly, asthmatics, children?); how are people harmed by PM2.5 in ambient air, if they are harmed at all (i.e., what biological mechanism?); and whether risk is the same for every area of the United States.
Perhaps the TCEQ simply had not reviewed the Rice study before it released this newsletter article, or perhaps the TCEQ is once again determining what it alone will accept as “sound” science and what it will not. If it had reviewed the Rice study, the TCEQ would have seen answers to its “many questions.” It would have seen a scientifically sound demonstration of the nature of the risk posed by exposure to PM2.5 in the air. Since the Rice study used data collected under the still existing 24‐hour PM standard, any question about at what concentration of PM2.5 risk may occur is answered — the daily concentration currently allowed! Professors Raun and Ensor determined that the current 24-hour PM standard does not serve its intended purpose of protecting public health. Who is harmed and how they are harmed is likewise clearly answered in the Rice study. As to TCEQ’s claim that co-pollutants are likely “confounding variables” affecting the relationship between PM2.5 and health effects and that “focusing on size-based PM2.5 may not adequately capture potential risks to human health,” the Rice study also looked at the effects of nitrogen dioxide, sulfur dioxide and carbon monoxide levels, but none were found to impact the occurrence of out-of-hospital cardiac arrests. Finally, while the TCEQ questions whether risk is the same for every area of the United States, the Rice study addresses the important question of what the risk is right here in Houston.
This landmark Rice study has provided mathematical and scientific validation of what most environmentalists, health professionals and emergency responders already know — that certain types of air pollution, including PM and ozone, have significant negative effects on cardiac and respiratory health. The TCEQ would better serve us all if it would depart from its all-too-often practice of criticizing and challenging scientific studies that it disagrees with and findings that it dislikes, and instead embrace studies and findings such as the Rice study that clearly and scientifically support better protection of our public health by ensuring better quality of our air.