Air Quality, Energy, and Climate in Southern California

By Aaron Katzenstein

The view from the Southern California Air Quality Management District:  the activities, the data and the issues remaining.

Signal Hill in the early 1940's. Early Los Angeles City Views (1925+). Water and Power Associates. Web. 3 Jan. 2015.  


Most of the pollution problems today in Southern California are caused by combustion of fossil fuels. Air pollution became most vivid in the 1950s, when there were a lot of uncontrolled emission sources, including backyard incinerators, automobile exhaust, and industrial processes. Smog became a four-letter word synonymous with Los Angeles:  the thick orange-brown layer that hung over the region,  the images of residents wearing gas masks and wiping their eyes as they walked down local streets. That Southern California’s skies today are much cleaner and clearer is a direct result of citizen action and political responses that lead to the 1976 creation of the South Coast Air Quality Management District (SCAQMD).

Three levels of government manage the region’s air pollution. The U.S. EPA sets federal standards for criteria of pollutants, identifying toxic air contaminants. The California Air Resources Board (CARB), and SCAQMD, are charged with monitoring the atmospheric levels of criteria pollutants and toxic pollutants (see explanation later), determining which compounds are not in compliance with federal standards, and jointly developing State Implementation Plans to develop pathways that will bring the region into compliance. The State Implementation Plans are referred to as Air Quality Management Plans, and must be submitted to EPA for their approval.  Overall, CARB is more focused on transportation sources and SCAQMD is more focused on stationary sources.  But because the majority of this region’s current air-pollution problems come from transportation—cars, trucks, busses, and ships—SCAQMD is working closely with CARB and other agencies to reduce emissions from these sources more and more.  CARB is also tasked with implementing the California Global Warming Solutions Act, also known as AB 32.

The region’s physical geography complicates air quality efforts in the region. The South Coast air basin is surrounded by mountains on three sides with the Pacific Ocean on the other.  This region experiences on-shore winds, which are a typical air flow blowing west to east.  They create an atmospheric inversion layer, trapping pollutants. These gases can then just simmer, developing other compounds like ozone. Because this process affects the entire region and emissions occur throughout the entire region, SCAQMD’s mandatory jurisdiction covers this entire bowl. So we regulate stationary sources such as refineries and the gas-pump nozzles that you fill your vehicles with. Also if you buy a can of paint in southern California, it will be low VOC paint, as required by our regulations.

What are air pollutants? These six pollutants—particulates, ozone, CO, NO2, SO2, and lead—are called ‘the criteria pollutants’. These are the ones the federal government wants us to monitor to ensure our Basin is meeting federal standards. We also have what are called ‘air toxic pollutants’ which include all industrial chemicals. Lately, the state has implemented greenhouse gas emissions regulations and SCAQMD is starting to monitor those throughout the basin at our 38 monitoring stations.

The region is in compliance for most everything, except for ozone, and fine particulate matter though we have areas of toxic hotspots.  These hotspots are typically in the vicinity of certain industries and along major highways and arterial roadways. One compound we are particularly interested in is diesel exhaust which is also a large contributor of black carbon, a climate forcer.

Many of the state policies and regulations are focused on Greenhouse gases and these policies and regulations are ground breaking in the United States. Air Pollution regulations that are developed in California and locally often are later adopted at the national and international levels. So, California’s efforts to regulate greenhouse gases, in my opinion, accelerated extremely swiftly and one hopes will lead to implementation elsewhere.  Additionally, the reductions in greenhouse gases also result in co-benefit reductions of toxic air contaminants and criteria pollutants.

The fine particulates we measure have several different sizes. Total Suspended Particulate matter is everything that we can suck into a filter. And that’s mainly for a visibility within the region. On days when the Santa Ana winds are blowing, you can see a lot of TSP airborne (and in our monitoring filters).

Among the measurements we calculate is PM10 (less than ten microns in diameter) and PM2.5 (2.5 microns or less in diameter). PM2.5 is directly emitted from combustion sources. Because it is also formed in the atmosphere, if you live in Riverside you might be breathing NOx emissions generated in Los Angeles that have blown over the Chino dairy area and reacts with ammonium nitrate, forming atmospheric particulates. The NOx emissions also form nitric acid that forms particles in the atmosphere.

The public health dangers associated with PM2.5 are linked to where they are lodged in our respiratory systems: they do not get stuck in our upper respiratory tracts but are absorbed deeper in our lungs.  Depending on what is in those 2.5 particles, different problems result. Something SCAQMD is beginning to assess are called ultra-fine particles. Health research indicates that those particles can cross cell membranes. This research is in the infancy stages of determining the implications for ultra-fines.

There is good news: the Basin’s ozone levels are going down. We’re starting to work on our next Air Quality Management Plan, and, the unfortunate thing is that all the low-hanging fruit is done. What we need to tackle now are the harder problems.. We need to bring the region into conformity for ozone and we have nine working groups examining different economic sectors so that they can sort out new pathways. These are pre-work groups, before formally starting the next AQMP, which is due in 2016.


Figure 1:  Health risk impacts as measured at each of the MATES III and IV monitoring stations.  Risks between studies have gone down due to controls. 

In October 2014, we released what we call our MATES-4 draft report Monitored Air Toxics Risk by Site). We conducted MATES-3 sampling from 2004-to 2006, and Mates-4 was conducted between 2012- and 2013. We see a large decline in the overall risk, especially from diesel-particulate matter. In California, diesel-particulate matter is considered a toxic air-contaminant, and with reason: it is the largest widespread toxic risk source within the Basin and accounts for 90 percent of our health risk. As a sign of how advanced California’s regulations in this regard are, the federal government does not yet consider diesel-particulate matter a toxic-air contaminant.

Regional energy use changed a little bit in the aftermath of the 2008 economic downturn, but it did not change much because the rate of consumption of energy in Southern California is so very weighted towards transportation.   We love our cars, we love the movement of our goods, and that embrace is reflected in this data: SoCal’s commercial residential sector energy needs are less than rest of America, but regional transportation needs overwhelm this efficiency. This also is partly due to our climate in Southern California and the energy efficiency efforts put in place many years ago.

Consider our carbon dioxide emissions from our transportation sector, which equals 134 million metric tons. If you add these emissions to those generated in the residential and commercial sectors, Southern California constitutes about half the state’s greenhouse gas inventory.  Roughly translated, this is the equivalent of ten billion gallons of gasoline, diesel, and jet fuel. Ten billion gallons will fill fifteen thousand Olympic sized swimming pools. Tackling this rate of consumption and the emissions it produces will be critical to the forthcoming AQMP planning process.


Figure 2:  NOx emissions shaown by energy usage within the South Coast Basin.  The majority of NOx emissions result from transportation combustion sources of fossil fuels.

There are a lot of climate change-adaptation discussions in California, especially in Southern California. We’re a member of the Los Angeles Regional Collaborative, which is discussing how cities are going to adapt to the shifting climate. This is particularly critical in this region, for if we’re starting to see more extreme temperatures inland, we’re going to see higher ozone levels as a result.

One of the strategies our agency is pushing is to bring more zero- and near-zero-emission technologies online, especially in the transportation sector. As shown earlier, the majority of our criteria, toxic, and greenhouse gas emissions are resulting from transportation.  We need widespread implementation of cleaner technologies, many of which are just coming on-line now or are being developed.  For example, when ships dock at the ports of Los Angeles and Long Beach they shut off their dirty diesel engines used for electricity needs and often plug into shore power. More innovative solutions like this will help us drive down the Basin’s emissions. That’s why I I tell my boss, “It’s an interesting time to be alive,” especially here in California. We have a big chance to make some huge changes in emissions with recent regulations, rapid alterations in technology, along with significant price declines in renewables such as solar PV, to help get zero- and near-zero electricity and transportation sources in place.

Consider the impact of AB32, California’s climate change legislation. It contains a scoping plan that lays out how the state is going to meet the 2020 and 2050 Greenhouse Gas (GHG) targets. The 2020 target mandates that the state roll back its GHGs to 1990 levels, and that by 2050 its GHG would be 80 percent below 1990 levels. We are on track to meet the 2020 level, but the larger challenge will be to meet the 2050 levels. Among the regulatory mechanisms that have been devised to achieve AB32’s goals are the state’s cap-and-trade program. There’s the renewable portfolio standard, all electricity consumption in California has to be met by 33 percent renewables by 2020.  Additionally, the state has a target of having 1.5 million electric vehicles on the road by 2025.   These regulations will also have a large impact on the reduction of criteria and toxic emissions.  This goes back to the co-benefit reductions between gases shown earlier and we are advocating for rapid implementation of these policies and regulations within the Los Angeles Basin.

On the technology side, there’s a lot of renewable energy coming into play and SCAQMD is helping incentivize the transition to cleaner technologies.  In order to attain federal ozone standards, reduce our toxic risks, and attain the 2050 target for greenhouse gases we need widespread implementation of zero and near-zero emission technologies.  The SCAQMD helps incentive the implementation and demonstration of these technologies.  We do this in part through registration fees paid within Southern California that result in alternative fueled or powered school buses, transit buses, and other local government fleets.  We also demonstrate new transportation technologies such as electrified or fuel cell powered heavy duty trucks and cars.  Additionally, the future of the electric vehicle is strong.  I drive an electric car and when I initially purchased the car there were more EV chargers than vehicles.  We now have the opposite problem even though we now have 3 to 4 vehicles per charger:  there are more drivers who want access to the chargers than we have chargers available! This demand, rightly enough, gives me hope for the future.