“This paper shows a correlation between prenatal exposure to sulfate and ammonium components and childhood autism diagnoses. There is absolutely no evidence within the paper to suggest that the former caused the latter. It could potentially cause great worry to the general population if they thought this paper demonstrated a causal effect, having already been exposed to inaccurate claims around Tylenol and vaccines as causes of autism. Reports like this contribute to the very harmful myth that autism is increasing in prevalence: robust evidence from many studies indicates that this is not the case, but rather more autistic people, especially women and adults, are being recognised and diagnosed (which is an excellent thing, both on a personal level but also on a socioeconomic one, since late diagnosis is associated with poorer health and suicidality). The wording and framing of the article, talking about ‘autism risk’, also contributes to harmful narratives in which autism is presented such as a disease, something negative to be eradicated or avoided; we know that these kind of messages are felt as deeply detrimental by autistic people and their families, who feel they’re living in a world where they’re unwanted and unacceptable. It is deeply disappointing that authors continue to contribute to these harmful narratives rather than following responsible guidelines in the way they speak about autism – thus harming the community they’re studying.”

“This study is showing correlation between air pollution exposure and potential cognitive development towards neurodivergence and autism.

“This study is not confirming air pollution exposure causes autism in children. This is because we do not know the biological pathways where air pollution could change neuro-development in this way. We do know that negative impacts on cognitive function are associated with air pollution exposure but most of this research is for an older age category.

“The study highlights important next steps around introducing socioeconomic variables alongside air pollution to suggest why an individual might be neurodiverse Vs neurotypical, another approach is called life course analysis where we model air pollution over different phases of life.”

This paper highlights the importance of early life environment in autism. Autism is often a multifactorial condition, where multiple factors, both environmental and genetic combine to cause the condition.

This large Canadian cohort reports a link between prenatal exposure to several specific chemicals in fine particulate matter (PM2.5) air pollution and also postnatal ozone (O3) exposure were associated with a higher likelihood of subsequent child autism. Several chemicals appeared to be important. An important next step will be to look at the combined effect of multiple air pollutant chemicals, including those generated inside the home.

Further, this work reinforces the importance of considering manufactured chemicals more generally to consider the combined effect of total chemical load. Consideration needs to be given that chemicals are not only inhaled but absorbed through the skin and also ingested. If chemicals are leading to similar biological effects in the body, then their additive or supra-additive effects will be important to consider.

We are investigating these issues in neurodevelopmental work at the Florey Institute, together with other Australian collaborating organisations. A key focus is the possible contribution of plastic chemicals in early life and this work is supported by the Minderoo Foundation. Our work indicates it is important to consider not only combined chemical effects but also child genetic vulnerability to these environmental exposures.