January 6, 2017 | One Friday evening last winter as I was walking down my block, I noticed a faint fuel smell. I don't live in a polluted area, and it was a clear and beautiful night. Inside the apartment, I noticed it again. Odors can travel in residential buildings, and I thought that whatever it was would soon vanish. And it did, but it returned. And I noticed it again outside, all the way down the block, and it started to worry me.

Years ago, my cousin described her intensely sensitive sense of smell like this: "I can tell you if someone standing across the room ate Cheez Doodles last week." She was kind of kidding and kind of not. My sense of smell is not that intense, but it's close. And the problem with being like this is that it takes a while for people to believe you - and sometimes things have to get worse before others discern the odor.

I went on with my life, but whenever I returned home, I was dismayed to find that the odor was lingering inside and out, all along the block. I had no idea of what to do or whom to call. When my super returned to the building Sunday night, I took a deep breath and told him that there was a fuel smell in my apartment, which is on the top floor. He said he would look into it, and a short time later I found him in the lobby, on the phone, looking stressed. When he got off the phone, he said, "You weren't the only one who noticed it." Others on the top floor had left him messages over the weekend. Our boiler was the source, and he had turned it off and was trying to schedule a visit to have it repaired. Whatever the cause of the problem, its emission was so strong that it could be detected along the entire block.

Of course, the moment he said that I hadn't been the only one who noticed the fuel smell, I stopped worrying. There was nothing to prove.

Part of the reason it's challenging to describe, report, or otherwise validate a noise issue is the idea that noise perception is entirely subjective. In mainstream media and scientific discourse for a lay audience, many articles begin with "Noise is unwanted sound." I wonder if so many authors use this definition because it is so brief and memorable. There are better ways to define noise.

One research team defines noise as "an unwanted sound or a combination of sounds that has adverse effects on health" ₁ while an environmental website defines noise as "an unwanted or disturbing sound which can interfere with normal activities for humans and wildlife, such as sleeping, conversation, reproduction, and communication, and disrupt or diminish one's quality of life."₂ Both are accurate, and they complement each other well. But sound can also not be unwanted and cause harm to hearing and other aspects of physical and mental health.

Like many forms of pollution, there are objective and subjective feelings about noise. Subjectivity with noise perception gets more attention partly because the term "annoyance" is used to describe a measure of human response to noise. In acoustics terminology going back half a century, "annoyance" is a measure of response to noise. The term is neutral. If there is evidence of annoyance (sometimes other terminology is used) or potential for discernible noise, then noise is a problem, and it needs to be prevented or resolved.

I found myself drawn to advocate for the elimination of horn sounds for mundane, non-emergency vehicle tasks because I found the technology so irrational. I am otherwise so oblivious to noise that bothers the average person that at times it takes effort for me to be sensitive to others' complaints about noise.

Recently, I stayed overnight in a hospital after elective surgery, and my room was outside the nurses' station. You could hear activity, voices, and laughter throughout the night, but it didn't stop me from sleeping. A sign on the wall read, "Our goal is to create a quiet and healing environment... ALWAYS... Please let us know if there is something preventing you from sleeping." I knew that if I said one word, the nurses would have reduced the sound level. I also knew that others on the floor might have found the sounds comforting.

Does this suggest that the negative aspects of noise are entirely subjective, and that people might even be taught to be less affected by noise pollution? Not at all. I argue that if someone like me, with relatively high tolerance for a range of sounds, is critical of a noise source - like horn-based non-emergency signaling - it may be affecting a broad range of people, many of whom will never complain.

When making decisions, manufacturers, policymakers, and enforcement agents may not consider people who are sensitive to noise. But when making any environmental decision, it is practical to plan and design for those who are most sensitive. That way you capture a range of those you will never hear from - like those who don't like to complain, children, pets, wildlife, and vulnerable populations who suffer in silence.

Ignoring noise complaints, like ignoring those with acutely sensitive senses of smell, is a bad idea. These are the very people we need to pay attention to when we plan, design, or respond to feedback and concerns. Things shouldn't have to get worse or fall into chaotic states before we admit that there is a problem.