Last updated February 16, 2018 at 4:54 pm
Everyday items round the house could be just as much to blame for urban air pollution as cars.
When you think of sources of urban air pollution, you probably think of transport, industries, or electricity generation. What you probably don’t think of is paint, perfume or cleaning products.
Yet new analysis from the US National Oceanic and Atmospheric Administration has surprisingly pointed the finger at exactly those – household volatile chemical products – as a major source of air pollution in our cities, contributing to close to 50 per cent of pollution.
The research examined volatile organic chemicals, which can waft into the air and react to produce either ozone or particulate matter, which leads to smog, and impacts on our health, including lung damage. A 2017 article published in The Lancet identified air pollution as one of the 5 biggest threats to our lives.
This is a separate type of pollution from carbon emissions, which are the driver of anthropogenic global warming and climate change.
The change in pollution
People use a lot more fuel than they do petroleum-based compounds in chemical products – about 15 times more by weight, according to the new assessment.
But despite this large difference in use, lotions, paints and other products contribute about as much to air pollution as the transportation sector does, according to lead author Brian McDonald.
“As transportation gets cleaner, those other sources become more and more important,” McDonald said. “The stuff we use in our everyday lives can impact air pollution.”
The change has come as governments and car manufacturers have focussed on developing engines and fuels which are cleaner and less polluting. So while in the past car and truck emissions or leaky gas pumps have been the major source of particulate pollution that we breath, as they’ve cleaned up their act and reduced their pollution the balance has changed.
“Gasoline is stored in closed, hopefully airtight, containers and the VOCs in gasoline are burned for energy,” said Jessica Gilman, a NOAA atmospheric scientist who was involved in the analysis.
“But volatile chemical products used in common solvents and personal care products are literally designed to evaporate. You wear perfume or use scented products so that you or your neighbor can enjoy the aroma. You don’t do this with gasoline,” Gilman said.
This means that as the use of petroleum as an energy source becomes less polluting, the free release of VOC’s from other sources, including consumer products, become more important.
The new study found that the balance has shifted far closer to 50-50.
“Overall, there is a hidden good news story here – VOCs from fuel use have started to decrease so overall the air is cleaner,” said Dr Jenny Fisher from the University of Wollongong, who was not involved in the study.
“Since the contribution from fuels has dropped, it is not surprising that chemical products, which have not been as tightly regulated, are now responsible for a larger share of the VOCs.”
Reassessing the balance
To find out how this balance shifted, the NOAA researchers reassessed air pollution sources by sorting through recent chemical production statistics compiled by industries and regulatory agencies, making detailed atmospheric chemistry measurements in Los Angeles air, and evaluating indoor air quality measurements made by others.
The scientists concluded that in the United States, the amount of VOCs emitted by consumer and industrial products is actually two or three times greater than estimated by current air pollution records. The current records also overestimate vehicular sources.
The Environmental Protection Agency estimates that about 75 percent of fossil VOC emissions comes from fuel related sources, and about 25 percent from chemical products. The new study, with its detailed assessment of up-to-date chemical use statistics and new atmospheric data, puts the split closer to 50-50.
The team found that they simply could not reproduce the levels of particles or ozone measured in the atmosphere unless they included emissions from volatile chemical products.
However, they also found that people are exposed to very high concentrations of volatile compounds indoors – often 10 times higher than they were outdoors.
“An important implication of this work is that these chemical products have largely been ignored when constructing the models that we use to predict air pollution – which impacts how we respond to and regulate pollutants,” said Dr Fisher.
“If we want to keep air pollution to a minimum, it will become increasingly important to take into account the VOCs from these chemical products, both in our models of air pollution and in our regulatory actions. This applies not only to outdoor air pollution but particularly to indoor air pollution – a major concern as we spend most of our time indoors.”
Historically so much focus has been put on transport to clean up its pollution and release of VOC’s into the atmosphere. And it’s been extremely effective.
However this finding shows it might now be time to spread our attention to other petroleum-based products, like those we use every day around the house without thinking, to ensure our air is healthy in the future.
It’s no longer just about cars.
The research has been published in Science.