Checkup on Health: Where there's smoke, there's pollution

Fireplaces are a major source of health-damaging soot

boy with inhaler
Wintertime smoke can cause soot or particle pollution linked to breathing and heart problems.

For many, the aroma of wood smoke is a comforting sign of the holidays and time spent around fireplaces with family and friends. Unfortunately, it can also mean the presence of airborne particle pollution, a potential health hazard to avoid and prevent.

Particulate pollution is a mix of specks and droplets of varying sizes and composition, ranging from chemicals, organic biological compounds and metals to dust and soil. Harmful particles can emerge directly from sources like smokestacks or unpaved roads, or result when chemicals react in the atmosphere. Vehicles, power plants, forest fires and other types of combustion are major contributors.

Nasty stuff

Epidemiological studies show that high levels of breathable particulates increase the incidence of heart and lung disease and deaths, said Carroll Cross, a professor of pulmonary and critical care medicine at UC Davis School of Medicine —though the link is complicated by factors such as climate conditions, the presence of other pollutants such as ozone and cigarette smoke, how close a person lives to a major highway and the specific size and surface chemistry of the particles.

Particulates can aggravate and exacerbate lung diseases such as asthma and chronic obstructive pulmonary disease, Cross said, and have been linked to irregular heartbeat, nonfatal heart attacks and even premature death in people with existing heart disease in some epidemiological studies.

There is also evidence supporting the idea that air pollutants, including particulates, increase the incidence of lung cancer in smokers. For example, Cross said smokers have higher rates of lung cancer in polluted urban areas such as Los Angeles and Philadelphia than do smokers in relatively unpolluted rural areas.

Among the nation's most polluted

The largest particles, known as “coarse” particulates, range between 2.5 and 10 micrometers in size, while “fine” particles are smaller than 2.5 micrometers. Both are much smaller than the typical 50-100 micrometer width of a human hair. The smaller the particle, the deeper it can penetrate into the lungs, and generally the more worrisome it becomes to health officials.

The Sacramento metro area does not meet federal or state health standards for fine particle pollution — and has even made the American Lung Association’s list of the ten most particle-polluted U.S. cities. During wintertime, residential wood burning is the largest single source of Sacramento’s fine particulate matter problems, according to the Sacramento Metropolitan Air Pollution Control District.

How to avoid particle pollution

Cross shared these tips to avoid particle pollution this winter:

  • Check air quality and stay indoors in times of heavy particulate exposure levels. The Sacramento air district posts current conditions on the Spare the Air web page at and provides “air alerts” about high pollution levels via email or text (sign up at
  • Check before you burn, and don’t burn during times of heavy pollution. From November to February in Sacramento County, residents and businesses are prohibited from using indoor or outdoor fireplaces, wood stoves, fire pits and chimineas that burn wood, pellets, manufactured logs or any other solid fuel on days when air quality is forecast to be unhealthy to breathe. The air district announces no-burn days through a toll-free telephone hotline at 1-877-NO-BURN-5 (1-877-662-8765), on the Web at, and through local media.
  • Drive less during these times, as car exhaust is a major contributor to urban atmospheric particulates.
  • Eat a healthy diet, but reduce outdoor activities that require increased or heavy breathing, such as running or tennis.
  • Don’t smoke – or quit. Cigarette smoke is the major example of a toxic, inhaled particulate substance. View UC Davis stop-smoking tips and resources 

Read more:

Air pollution linked to bronchitis in preschoolers 

Housefly may act as “canary in coal mine” for air pollution