Lung function and self-rated symptoms in healthy volunteers after exposure to hydrotreated vegetable oil (HVO) exhaust with and without particles.

"Declarations Ethics approval and consent to participateThe study was approved by the Swedish Ethical Review Authority (registration no. 2019–03320) and performed in accordance with the Declaration of Helsinki and included obtaining informed written consent. Consent for publicationNot applicable. Competing interestsThe authors declare that they have no competing interests. Competing interests The authors declare that they have no competing interests."

"Funding This research was financed by the Swedish Research Council FORMAS (2016-00824). Jakob Löndahl acknowledges funding from the Swedish Research Council for Health, Working Live and Welfare FORTE (project number 2017-00690). Open access funding provided by Lund University."

"Volunteers were recruited via Lund University online channels and posters. Of the 25 volunteers who underwent the initial medical examination (spirometry, medical history), 19 fulfilled the inclusion criteria and were consecutively selected for the study. The inclusion criteria were the following: men or non-pregnant women; 20–65 years old; no symptoms or diagnosis of lung disease or asthma; normal standard ECG reading; no allergy or cardiovascular medication; non-smoker the last three years. All except one of the selected participants underwent all three exposures. One person only participated in the exposure to HVONOx. Characteristics of the study group are summarized in Table and in detail in Additional file : H. Out of the 7 former smokers, only one was considered a previous heavy smoker (smoked up to 2 packages of cigarettes a day for 10 years) but had been a non-smoker the past 30 years. The smoking habits of the other 6 former smokers varied between < 1 up to 35 cigarettes a week for 1–5 years, and all had been smoke-free the last 4 years. No subjects regularly used any medication except combined oral contraceptive pill (1/19), vitamin C (1/19) and vitamin D (1/19). The study was approved by the Swedish Ethical Review Authority (registration no. 2019-03320) and performed in accordance with the Declaration of Helsinki. Declarations: Ethics approval and consent to participateThe study was approved by the Swedish Ethical Review Authority (registration no. 2019–03320) and performed in accordance with the Declaration of Helsinki and included obtaining informed written consent.: Consent for publicationNot applicable.: Competing interestsThe authors declare that they have no competing interests. Ethics approval and consent to participate: The study was approved by the Swedish Ethical Review Authority (registration no. 2019–03320) and performed in accordance with the Declaration of Helsinki and included obtaining informed written consent."