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Pollution confirmed as cause of cardiac arrest in large study

Kathleen Blanchard's picture
Pollution linked to cardiac arrest in massive study.

Researchers have confirmed the link between pollution and higher rates of cardiac arrest that comes from a massive amount of data collected in the Houston area. The city is number eight in the US for highest number of high ozone days.

The study was carried out in an effort to save lives, the authors say. The impetus is to train emergency medical personnel to be on alert for high ozone days. The investigators note it’s important to get more of the public trained in CPR.

The analysis found even small increases in fine particular matter in the environment of 6 micrograms per day over two days raised the risk of out of the hospital cardiac arrest (OHCA) by 4.6 percent.

Rising ozone levels had the same effect, but over a shorter period of time. Each increase of 20 parts per billion over one to three hours raised the chances of cardiac arrest up to 4.4 percent.

Rice University statisticians Katherine Ensor and Loren Raun presented the findings at the American Association for the Advancement of Science (AAAS) taking place in Boston.

The results are based 8 years of data collected from air quality monitors and more than 11,000 coinciding cardiac arrests logged by Houston Emergency Medical Services (EMS).

Cardiac arrest related to pollution affects anyone with an existing health condition, the authors noted, even for those without pre-existing heart problems.

Past studies have linked air pollution to risk of stroke from the effect of fine particulate matter, defined as airborne particles smaller than 2.5 micrograms. The current study looked at the effect of ozone as well that the researchers say is more difficult to control than small particles that come mostly from carbon emissions.

According to the EPA, fuel combustion from motor vehicles, power generator and industry in addition to fireplaces and wood stoves form fine particles in the air that can travel long distances. They can also be formed in the atmosphere from nitrogen oxides and sulfur dioxide.

Coarse particles that lend to pollution come from vehicles traveling on unpaved roads, materials handling, industrial crushing and grinding operations and dust carried by the wind.

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David Persse, Houston Fire Department EMS physician director and a public-health authority for the city of Houston said EMS personnel have long suspected ozone and other types of pollution negatively impact health and this study validates it’s so, “mathematically and statistically”.

The researchers found more than 90 percent of people who received chest compressions (CPR) by EMS died. Cardiac arrest related to pollution was more frequent during hot summer months and more prevalent among African-Americans, men and people over age 65.

Loren Raun says Houston has implemented educational programs for ‘at-risk’ communities, “…where they're now doing intensive bystander CPR training."

The chances of surviving cardiac arrest drops 10 percent for every minute a victim is left unattended. Immediate cardiopulmonary resuscitation saves one out of every 26 to 36 people, Raun said.

Houston’s Health and Human Services Department says though the city’s efforts can help mitigate the negative health consequences of pollution, the primary strategy should be to improve air quality.

At the same AAS meeting, Rice environmental engineer Daniel Cohan discussed uncertainties of the health benefits related to controlling ozone pollution. He notes current EPA focus is on peak conditions. He suggests there may be benefits for health from reducing ozone levels year-round.

The current EPA standard is set at 75 parts per billion (ppb), which the researchers say serves its purpose. But standards for fine particulate matter pollution of 35 micrograms per cubic meter are too high to save lives.

Education and training will help save lives from the ill health effects of pollution. But Ensor says, "At the same time…we want to celebrate its continuing reduction."

You can help keep air cleaner in your own city by carpooling, biking to work when possible, turning off lights when not in use, keeping your car engine tunes and tires properly inflated and sealing cans with vaporizing chemicals, such as pain, tightly and storing them properly.

The finding confirms the link between pollution and death from cardiac arrest. Fine particulate matter from carbon emissions contributes to a variety of health problems including asthma, chronic bronchitis, and premature death. The researchers for the current study say action can be taken to save lives such, as refined warnings for people at risk.

Rice University
February 17, 2013

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