Air quality improving but threatened by drought, report shows

California’s air quality has improved substantially in the past few years, but the ongoing drought is having a troubling impact on the levels of particulate pollution, according to a new report released Thursday.

The 2015 “California Progress Toward Clean Air” report shows air quality data for all 35 air districts in the state.

The report highlights that since 1990, the state’s population has increased by 29 percent, the number of vehicles on roads has increased by 32 percent and the economy has grown by 83 percent, but statewide emissions have decreased by more than 50 percent.

The San Joaquin Valley Air District has also recorded major progress in air quality over the past 15 years, local air officials said, but challenges, as outlined in the report, remain. The report is put together by the California Air Pollution Control Officers Association using air quality data from 2014, the latest available.

According to the air district, the Valley’s challenges in combating air pollution are unique in comparison to other areas because of its geography, topography and weather.

Jamie Holt, the air district’s chief communications officer, said that it is clear the Valley creates less pollution than other metropolitan areas in the state. However, natural challenges such as the Valley’s bowl shape, hot weather and prolonged periods of stagnant air are ideal conditions to trap pollutants.

Another key problem is the drought.

No rain means the ground is drier and strong winds can blow around loose soil from dry lake beds and empty fields, the report explained. Dry surfaces also allow vehicles to kick up dust. The loose dust and soil can boost concentrations of fine particulates.

Holt explained that weather patterns that keep rain from coming into the Valley are the same ones responsible for stagnant air. Periods of no air flow leave no means for pollution to escape the area, allowing pollution to build up over time, she said.

Poor air quality has been linked to serious health problems. Exposure to fine particulate pollution can affect the respiratory and cardiovascular systems. For example, it can aggravate asthma attacks and worsen other lung ailments such as emphysema and chronic obstructive pulmonary disease.

According to the report, recent Air Resources Board calculations found that exposure to current levels of particulate matter is responsible for about 7,300 cardiopulmonary-related deaths per year in California. The bulk of those deaths happen in the most polluted areas of the state, including the San Joaquin Valley.

It is estimated that about 1,300 deaths in the Valley are linked to cardiopulmonary illnesses.

Holt explained that tailpipe emissions from older vehicles are one of the most challenging public health concerns in the Valley. Evidence also shows that pollutants from residential woodsmoke during winter and wildfire smoke during the summer are also top public health issues, Holt said.

But not all is bad news. Despite the strings of triple-digit temperatures, wildfires and stagnant air present in summer 2014, the air district recorded no violations of the one-hour ozone standard for the second year in a row. And even with poor weather, particulate matter levels have been kept from climbing even higher.

Holt said this is in large part due to the district’s regulations and grant programs that promote cleaner work equipment and practices. For example, the air district works with Valley businesses on upgrading to equipment that would help with air quality improvement efforts, such as replacing old tractors and diesel trucks.

“We’ve made significant improvements,” Holt said. “But we’ve got a long way to go.”

This story was originally published April 9, 2015 at 7:30 PM with the headline "Air quality improving but threatened by drought, report shows."