Do Singaporeans realize that burning joss papers and joss sticks generates airborne carcinogens, in the same way as smoking cigarettes causes cancer? It's up to you to follow your own religious beliefs, but it's bad ethics and bad karma to cause harm to others.
Burning joss papers and joss sticks in HDB corridors is like forcing your neighbours to smoke carcinogenic cigarettes, and large scale burning during 7th month festivals is like forcing all other Singaporeans of other religions to smoke carcinogenic cigarettes.
For the record, no Chinese deity or Buddha ever instructed their followers to burn joss papers and joss sticks. The concept of burning incense or joss papers is a completely cultural issue fallaciously ascribed to 'religion' (just like how wearing the hijab and FGM are not actually Islamic requirements but merely cultural, but wrongly claimed to be religious requirements).
Ironically, there is very real bad karma for burning incense or joss papers and inflicting carcinogenic harm on others. There are always ways to improve one's practices to make it more ethical, helpful and healthy for others, it only takes the open-mindedness and willingness to do so.
It may be acceptable cultural practice back then, when there was no modern medical science to speak of, but today when medical science has clearly shown this activity's carcinogenic properties, you'd think humans would be intelligent enough and ethical enough to evolve their cultural practices to minimize harm to others and to themselves.
2016 case : Sg man with China wife (victims) vs Singaporean aunties (perpetrators)
http://theindependent.sg/video-of-prc-scolding-locals-for-burning-joss-papers-goes-viral/
2015 case : Elderly Singaporean couple (perpetrators) vs Young Singaporean couple with baby (helpless innocent victim)
http://news.asiaone.com/news/singapore/caught-camera-neighbours-lash-out-each-other-over-joss-sticks
Burning joss sticks and joss papers (for exactly the same reasons as why the cigarette smoke and haze from burning Malaysian landfills or Indonesian forests are carcinogenic) have been medically proven to be carcinogenic :
https://www.theguardian.com/science/2008/aug/26/incense.cancer
https://www.sciencedaily.com/releases/2015/08/150825083844.htm
http://www.reuters.com/article/us-incense-cancers-idUSPAT56944620080825
http://www.drweil.com/health-wellness/body-mind-spirit/cancer/is-incense-a-cancer-threat/
http://undergroundhealthreporter.com/fact-or-myth-is-burning-incense-bad-for-your-health/
http://www.nhs.uk/news/2015/08August/Pages/Is-incense-smoke-more-dangerous-than-tobacco-smoke.aspx
http://www.dailymail.co.uk/health/article-3210400/Could-incense-toxic-cigarette-smoke-burn-sticks-release-compounds-linked-cancer.html